Yes - historically Blue Peter was always live. I think they started pre-recording some episodes when it had CBBC-only versions as well as CBBC on BBC One editions. I think there was a trend to pre-recording when the show was still coming from a 'big' studio (TC4 etc) in TVC, not sure if this continued when it moved to a 'small' studio (TC2)
From the 60s until the 90s it was definitely always live when it was in the studio, though there were occasional 'filmed' shows, like the Summer Expedition episodes. For a long time it didn't use Autocue (this was introduced when Yvette Fielding started presenting I think), and the show would often be radically re-ordered by the editor, Biddy Baxter, after rehearsals. This really kept the presenters on their toes.
This is broadly right, although there were examples in the sixties of it being pre-recorded, and the famous example is Lulu the elephant, they've even said on the show now when showing the clip that the episode was pre-recorded because if it had been live it would have already been faded out as it was over-running. At that point in the late sixties, much to Biddy's dismay, they were pre-recording the Thursday show every week for about three months because there weren't enough studios available.
As mentioned, when it went three times a week, the Friday episode was indeed recorded straight after the Wednesday one but all the presenters and crew hated that and it was the first thing Steve Hocking changed when he took over. Certainly the Friday show was love at the turn of the century. When it was five days a week on CBBC but only three on BBC1, there were still only three "proper" shows a week with the other two being re-edits or a full-length film, and one of the CBBC ones was live and repeated the next day on BBC1, I can't remember how it worked now.
When they moved to TC2 as part of the radical revamp in 2007, for a while, when it was two shows a week it used to that they'd be live one week and then the next week's shows would be pre-recorded (a bit like Top of the Pops when it was on Sundays in its final year and one show a month was recorded at the same time as the previous week's). But now I think it's always live when they're doing a proper show at MediaCity, given they invite and read out correspondence on a set topic.
I also feel like their current audience have no clue about Blue Peter's past. Certainly when Inwas younger they regular spoke about past presenters, features etc and addressed birthdays for the show etc but now, to a new viewer, Blue Peter has an odd name, weird 'pointless' logo and hasn't a clue for how long it's been on air. I know they celebrate the big anniversaries but no longer do they say 'we're 56 years old today!'
I don't think they ever mentioned specific anniversaries other than the big ones, most obviously because they were not usually on the actual birthday. As for the history, the new title sequence which started last week features the logo on "waves", they had a piece about the Blue Peter steam train the other week and talked about its history, Yvette Fielding was on it on Pancake Day to judge their pancakes (and they showed the famous clip of her), they've just expanded the garden and dd a piece about its history, plus also put their handprints in concrete to go alongside the old presenters which they pointed out, and of course when they did that MI5 competition the other week it was called Project Petra and they explained why. And that's just in the last six months. I don't know how much else they're supposed to do without it becoming a programme about Blue Peter.
That had nothing to do with the number of episodes aired. IIRC, one of the presenters had a baby, a new one was hired to cover maternity leave and then stayed on. When the next person left, they weren't replaced.
Er, not quite, because although Zoe Salmon ostensibly arrived as "cover" for Lovely Liz Barker in 2004, Lovely Liz had actually already come back by the time she started, and then after her arrival, Simon Thomas left and was replaced by Gethin Jones. So they still had five hosts. The reason they didn't replace Lovely Liz when she left was because a) she was irreplacable and b) they weren't doing five days a week on CBBC anymore.